If you're using Terra-Vet 10 to treat chickens for chronic respiratory disease (CRD air sac disease) caused by Mycoplasma gallisepticum and Escherichia coli, then 400-800 mg/gal per day is the proper dosage levels (and, if so? I'd mix at 800 mg/gal ~'-)
If you're not treating CRD w/in...